Behavioral science initiatives to reduce individuals' climate footprint

Last registered on May 13, 2024


Trial Information

General Information

Behavioral science initiatives to reduce individuals' climate footprint
Initial registration date
May 13, 2024

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
May 13, 2024, 12:46 PM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.


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Primary Investigator

University of Massachusetts Amherst

Other Primary Investigator(s)

PI Affiliation
Linnaeus University
PI Affiliation
University College London

Additional Trial Information

In development
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
This project examines how consumers respond to carbon footprint information. To this end, we run an RCT using a mobile app that differentially exposes participants to information about their carbon footprints. The app provides detailed and personalized information based on users' consumption. We investigate how consumption and other behaviors change in response to exposure to this information.
External Link(s)

Registration Citation

Chan, Nathan, Jakob Enlund and Jonas Hjort. 2024. "Behavioral science initiatives to reduce individuals' climate footprint." AEA RCT Registry. May 13.
Experimental Details


We will differentially expose participants to messaging about their consumption through a mobile app.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Political behavior and attitudes
Primary Outcomes (explanation)
Consumption will be measured using bank transaction data and register data. We will measure consumption in terms of carbon footprint and expenditures/purchases in various categories.
Political behavior and attitudes will be measured using register and survey data. We will link register data on voting participation as a binary measure of political behavior. We will also provide subjects an opportunity to donate to an environmental cause and to sign an environmental petition as measures of political behavior. In terms of the survey, we will ask participants about their political preferences, their voting choice in the EU parliament elections, their opinion on environmental policies, and their opinion on the role of government and individual responsibility for confronting societal challenges. As an additional measure of political behavior, we are planning follow-ups with subjects to learn whether they have taken part in a climate demonstration.

Secondary Outcomes

Secondary Outcomes (end points)
Green investments
Carbon literacy
Perceived behavioral plasticity and intention to reduce carbon footprint
Secondary Outcomes (explanation)
Investments (e.g., stock portfolio, pension fund choices) will be observed through register data. We will construct a measure of how green the participant's investments are.
After exposure to treatment, we will gather survey data from participants about their knowledge of the carbon intensiveness of common activities. This outcome will help shed light on users’ learning and the informational value of the treatment.
As part of the treatment, users will be presented with a set of “action cards” that describe measures they can take to reduce their carbon footprints. We will observe and analyze their choice of which action cards they choose to save, which indicates the actions they would like to undertake, in whole or in part, in the next 6 months. We can subset our analysis of consumption outcomes based on the action cards saved by users, which may shed light on mechanisms for the treatment effect.

Experimental Design

Experimental Design
We will differentially expose participants to messaging about their consumption through a mobile app. Participants will be randomized into two versions of the mobile app: (i) a carbon footprint calculator and (ii) a financial management calculator. Both versions of the app will have a similar look and feel, but the treatment (carbon footprint calculator) will expose participants to personal responsibility messaging for addressing climate change.
Experimental Design Details
Not available
Randomization Method
randomization done in office by a computer
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
3000 individuals
Sample size: planned number of observations
3000 individuals
Sample size (or number of clusters) by treatment arms
1500 individuals control app; 1500 individuals treatment app
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
With an intended sample size of 3000 individuals and 80% power, we will have an MDE for consumption (carbon footprint) on the order of 0.04 log points. In pilot data, the mean for ln(carbon footprint + 1) is 4.14 and the standard deviation for this outcome is 1.37 log points, so our MDE is roughly 3% of a standard deviation.

Institutional Review Boards (IRBs)

IRB Name
Swedish Ethical Review Authority
IRB Approval Date
IRB Approval Number